This invention relates generally to ink recording methods, and more particularly, to methods for drying wet inks printed onto a media sheet.
Many inks, including thermal inkjet inks, are composed of a substantial amount of water. During print recording, ink drops are ejected onto a media sheet, wetting the media sheet. The recorded ink dries by evaporation of the liquid content leaving the ink resins remaining as a recorded marking. Conventionally, the evaporation occurs by letting the inked media sheet stand at ambient temperature.
While the ink remains wet on the media sheet, there is a risk of smearing the ink and thus losing the quality of the recorded marking. Thus, the drying time of the ink effects when the next media sheet can be printed. In particular, the drying time for wet ink printing often is a significantly limiting factor to print throughput speed. One approach for achieving improved print throughput speed has been to include a one-sheet buffer area. The buffer is formed by output rails. When a media sheet is printed, it is moved along the output rails where it is suspended above an output tray. By doing so, the top sheet in the underlying output stack is given additional time to dry. When the next sheet is printed, the prior sheet is dropped onto the output stack giving this next sheet additional time to dry. This partially offsets the negative impact that drying time has on print throughput speed. However, drying time still is a significantly limiting factor in print throughput speed. As the desire for still faster print throughput speeds continues, additional techniques are needed. It is known to use a heater and/or fan to speed up the drying process. Heating is an effective method for reducing the evaporation time. A disadvantage of these approaches i s the energy cost of generating the heat or powering the fan.
In a method and apparatus where ink is recorded onto a media, the ink is freeze-dried on the media.